生平

崇禎十五年（1642年），李光地出生於富紳之家。史載其自幼穎異，五歲便入塾從師授讀，「未嘗一啟齒，發聲試之，輒已成誦，不失一字。善屬對，矢口驚人。塾師弗能教也」。十三歲時已經遍讀群經，十八歲編寫《性理解》，十九歲寫《四書解》，二十歲寫《周易解》，二十四歲輯《歷像要義》，二十五歲通律呂之學。

李光地因「賣友案」而於士林聲名狼藉。三藩之亂時，耿精忠佔領福建，臺灣的鄭經起兵攻泉州，李光地一家匿藏於深山，鄭經、耿精忠誘降，李光地嚴拒，遠避深山。與李光地同為康熙九年（1670年）進士的陳夢雷，因在福建，遭到耿精忠掠去。陳夢雷運籌，李光地通謀，由夢雷探聽耿軍軍情，光地上蠟丸密疏，向清廷提供福建前方情報，透過福建籍的大臣富鴻基轉述。後來果然幫助清兵大破耿軍，李受到康熙讚許，但李光地早就將奏章的「陳夢雷」之名刪去，以獨吞功勞。平叛之後，身陷叛軍的陳夢雷便成了附逆罪臣，逮捕下獄，貶戍奉天。李光地卻扶搖直上，官至文淵閣大學士。李光地非但不救陳夢雷，反而落井下石，人稱「賣友」。

陳夢雷被逮入獄，悲憤至極，於七月份寫下了《告都城隍文》，揭露李光地的背信棄義行為。陳夢雷十分憎恨李光地，罵他是「欺君負友」之徒，還寫了《與李安溪絕交書》（又作《與李光地絕交書》）。康熙十九年（1680年），刑部尚書徐乾學（顧炎武外甥，徐乾學不承認李光地是顧炎武的學生）主其獄。竟代李光地起草一份疏稿，反映陳夢雷在耿精忠叛亂時的真實表現，逼李光地上奏。李光地義理難卻，乃具名。唯獨至此仍不肯直言陳夢雷參與定策功勞，僅請求寬貸其人而已，最後陳仍流放奉天。

康熙三十三年（1694年），李光地任順天學政，康熙三十七年（1698年），擔任直隸巡撫。為迎合康熙對西學的愛好，李光地曾與梅文鼎等人交流學術，而且命其弟李鼎征、其子李鐘倫隨梅文鼎學習數學。康熙四十一年（1702年），李光地向康熙帝推薦其著作《歷學疑問》，康熙帝讀後大為折服，次年南巡，特召至龍舟中長談。

康熙五十七年（1718年）五月，李光地病逝京寓。雍正元年（1723年）被追贈為太子太傅。曾奉敕編纂了《性理精義》、《朱子全書》、《周易折中》等書。是清初道學家的代表。而陳夢雷實際參與編纂《古今圖書集成》。

評價

李光地研究理學，倡言禮樂，實行海禁措施，導致近海百里無人煙，限制了農耕漁礦多種產業的發展，對康熙中年的決策有決定性的影響。晚年的李光地仍大受康熙寵信，出任吏部尚書、文淵閣大學士等職。康熙稱他「謹慎清勤，始終一節，學問淵博。朕知之最真，知朕亦無過光地者」。太子允礽被廢後，李光地開始輔助後來的雍正帝。雍正帝稱李光地為「一代之完人」。

《四庫全書總目提要》曾評其曰：「光地之學，源於朱子，而能心知其意，得所變通，故不拘墟於門戶之見。其詁經兼取漢唐之說，其講學亦酌採陸王之義，而於其是非得失，毫釐千里之介，則辨之甚明，往往一語而決疑似。」但是在全祖望看來，李光地根本是個偽君子：「其初年則賣友，中年則奪情，暮年則居然以外婦之子來歸。」

Biography

Li was a native of Anxi County, Fujian Province. In 1670, he was promoted to the rank of jinshi and moved to Beijing, leaving his brother Li Guangpo behind to look after his family. Li's career prospects improved when the Emperor pacified Fujian and acted on Li's suggestion to defeat Wu Sangui. He also helped defeat Geng Jingzhong, persuading his friend Chen Minglei to work as a spy in Geng's camp. Later in life, he was responsible for planning Shi Lang's conquest of Taiwan. During the course of his life, Li held various court positions, including Chancellor of the Hanlin Academy, Governor of Zhili and Grand Secretary, and positions on the Board of War, Board of Civil Service and the Board of Public Works.

Li's philosophy was rooted in the Cheng-Zhu school. However, despite being a follower of Zhu Xi he did not entirely disregard the teachings of Zhu's rivals Lu Jiuyuan and Wang Yangming. He also highlighted similarities between the teachings of Confucius and those of Buddha and Lao Tzu. Li felt that human nature (which he believed to be inherently good) was the ultimate subject of his study, and that nature was the guiding principle on which to base human morality. He had an interest in the sciences.

Li wrote or edited a number of philosophical texts, including the Complete Works of Master Zhu (Zhuzi daquan), the Essential Ideas of Nature and Principle (Xingli jingli) and the Interpretation of the Meaning of the Four Books (Si shu Jieyi). An expert on the I Ching, he also wrote two books on the subject, the Penetrating Discourse (Zhouyi tonglun) and the Balanced Annotations (Zhouyi zhezhong); the latter took the (at the time) unusual editorial step of segregating the original text of the I Ching from its subsequent commentaries. A complete collection of Li's works (around thirty books) was published around a hundred years after his death, entitled the Complete Works of Rongcun (Rongcun quanji).